Re: [PATCH 2/8] pstore: Do not use crash buffer for decompression

From: Joel Fernandes
Date: Thu Nov 29 2018 - 21:26:42 EST


On Thu, Nov 29, 2018 at 02:06:39PM -0800, Kees Cook wrote:
> On Tue, Nov 13, 2018 at 11:56 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > On Fri, Nov 2, 2018 at 1:24 PM, Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> wrote:
> > > On Thu, Nov 01, 2018 at 04:51:54PM -0700, Kees Cook wrote:
> > >> + workspace = kmalloc(unzipped_len + record->ecc_notice_size,
> > >
> > > Should tihs be unzipped_len + record->ecc_notice_size + 1. The extra byte
> > > being for the NULL character of the ecc notice?
> > >
> > > This occurred to me when I saw the + 1 in ram.c. It could be better to just
> > > abstract the size as a macro.
> >
> > Ooh, yes, good catch. I'll get this fixed.
>
> I spent more time looking at this, and it seems that only the initial
> creation of this string needs the +1, since all other operations are
> byte-based not NUL-terminated string based. It's a big odd, and I
> might try to clean it up differently, but as it stands, this is okay.
> (See inode.c which doesn't include the trailing NUL byte.)

Ok. Yes it does seem a bit inconsistent but I agree its not an issue for this
particular patch. Sorry to waste your time, thanks!

- Joel